Project modernization (#630)

* Fixed boats falling and a TP glitch #266

* Replaced every C-style cast with C++ ones

* Replaced every C-style cast with C++ ones

* Fixed boats falling and a TP glitch #266

* Updated NULL to nullptr and fixing some type issues

* Modernized and fixed a few bugs

- Replaced most instances of `NULL` with `nullptr`.
- Replaced most `shared_ptr(new ...)` with `make_shared`.
- Removed the `nullptr` macro as it was interfering with the actual nullptr keyword in some instances.

* Fixing more conflicts

* Replace int loops with size_t and start work on overrides

Minecraft.World/TileUpdatePacket.cpp

@@ -31,7 +31,7 @@ void TileUpdatePacket::read(DataInputStream *dis) //throws IOException
 	y = dis->readUnsignedByte();
 	z = dis->readInt();
 	
-	block = (int)dis->readShort() & 0xffff;
+	block = static_cast<int>(dis->readShort()) & 0xffff;
 
 	BYTE dataLevel = dis->readByte();
 	data = dataLevel & 0xf;